Current retail store product display practices typically require packaged consumer products to be left unattended and, therefore, subject to malicious tampering by unscrupulous individuals. Such tampering may occur with any packaged product, but products packaged in reclosable container assemblies are especially vulnerable because a closure member can be removed from the container and replaced, thereby concealing the fact that entry to the container has occurred. In order to protect a consumer from unknowingly purchasing a tamper damaged product packaged in a reclosable container, it is important to provide evidence which will alert a purchaser or the seller that the container has been opened.
Because of the hazards to both the purchaser and the seller which may be associated with contaminated or adulterated foods, merely providing evidence that a package has been opened is not sufficient. It is also important that evidence of tampering anywhere on a container-closure member attachment be presented in a readily apparent, non-concealable manner so that a consumer will be apprised of a potential problem even if he is not consciously looking for such evidence.
In the past, the problem of preventing undetected entry into a closed reusable container has been recognized. For example, containers and closure members of the type disclosed in U.S. Pat. Nos. 3,753,511, 3,979,003 and 4,190,175 have been developed to protect against unauthorized opening of a closed container by providing a tear-off portion of the closure lid which is damaged by manipulation of a pull tab. However, such devices may not provide evidence of unauthorized entry or attempted entry into the closed container at all locations on the closure member-container joint, and any evidence which might be produced may be concealed and not readily apparent. Furthermore, in such arrangements, unauthorized entry to the contents of the container may be made by working one's fingers under a tearable portion of the closure member or simply by exerting sufficient upward force on the closure to work the closure member off the container without damaging the tear strips, thereby accomplishing entry without a readily visible indication thereof.
The tamper indicator for a container closure disclosed in U.S. Pat. No. 4,037,748 is an improvement over the just mentioned devices, as this device includes a notch on the inner surface of a tear strip adjacent to a tab used to operate the tear strip for preventing someone from pushing the cover up by using the tear strip tab. The notch is designed to break on manipulation of the tab. However, even this improved device does not provide readily apparent and non-concealable evidence of attempted entry at locations other than adjacent to the tear tab, and the evidence may be concealed or missed because it is located beneath the tear tab. Additionally, this single notch type of tamper indicator can sometimes be defeated by carefully applying an upward force to the container closure on the side thereof opposite to the notch to either remove the closure or to slip some type of tampering implement under the closure and into the container. Force sufficient to accomplish this can often be applied at locations remote from the notch without breaking the notch.
The tamperproof closure member disclosed in U.S. Pat. No. 4,244,479 includes a plurality of circumferentially spaced apart tear grooves or slits on the outside of a tear-indicating sleeve for indicating attempts to remove or tamper with the tamper-indicating sleeve at various circumferential locations, and thus is an improvement over the previously patented devices. However, these grooves on the outside of the tamper-indicating sleeve are subject to providing evidence which might be erroneously confused with the grooves themselves and thus missed or overlooked during a casual inspection. The location of each groove is readily apparent to a prospective tamperer, and if breaking the groove cannot be avoided, the break may be sufficiently concealed within a groove to be missed by a consumer who may not be consciously looking for such evidence. Further, material might be injected to conceal a break in the innermost surface of a groove.
There is no provision in any prior art closure tamper indicator for automatically orienting the forces tending to produce the evidence of tampering so those forces are always applied to the most sensitive portions of the tamper indicator. It can be quite important to both the consumer and the seller to know of attempted entries as well as actual entries because of the potential problems which could arise from tamper damaged products.
The prior art therefore, has failed to provide a tamper indicator for a reclosable container which provides immediately apparent, unconcealed evidence at a number of locations that the container has been tampered with.